Classes and Objects

A class is a template, used to create objects from. Classes can include Properties and Methods (Traditionally known as, variables and functions), which can be used by other functions within the class, or even from the outside.

Variables inside the class can either be declared as public or protected. Public variables can be accessed from everywhere, and protected can only be accessed from within the class itself and by classes that inherits them.

If a property (AKA: variable) is declared using the private keyword, it will only be accessible from within the class.

Properties

When variables are declared inside a class, they will often be referred to as properties. But, often people will also use the variable term. An example of variables being declared in a class can be seen below:

class MyClassName {
 public $Property1 = 'Hallo hallo!';
 public $MyVariableName = 'Hallo dude!'; // Another Property
}

To access these variables, we first need to create an object from the class, this can be done by writing new when declaring a variable:

$MyObject = new MyClassName(); // Creates an object from the class

We can then output or change the variable values as we wish:

echo $MyObject->Property1 ."<br>";
$MyObject->MyVariableName = 'My House'; // Changes the property value
echo $MyObject->MyVariableName; // Outputs the property value

Methods

When functions are created inside classes, they are referred to as methods. A simple method, which everyone should be able to understand, is shown below:

class MyClassName {
 function SayHallo() {
   return 'Hallo';
 }
}

$MyObject = new MyClassName();
echo $MyObject->SayHallo();

The method simply returns the "hallo" value, and will write "hallo" when used with echo.

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